The present disclosure relates to bone and joint fixation and instrumentation and methods for preparation and implantation of these devices. Joint fixation may be necessary in cases of pain and inflammation due to cartilage degeneration, nerve impingement, spinal misalignment, and motion instability. The primary examples described herein illustrate how this concept is applied to the facet joint, but this concept applies equally to other joints where similar causes of pain and inflammation are indicated.
Facet fixation devices are typically implanted as a minimally invasive means of posteriorly stabilizing the spine. Biomechanical studies have shown that facet screw systems perform similarly or better than pedicle screw systems. Many commercially available facet screws require a complex and timely oblique fluoroscopic technique to achieve the proper placement trajectory. The facet fixation system disclosed herein employs a simple pedicle targeting trajectory requiring only M/L and A/P fluoroscopy. The cap geometry reduces placement sensitivity and allows the surgeon to capture and compress an increased bone surface, while optionally lateralizing the implant to better accommodate interspinous process access.
Those of skill in the art will recognize that the following description is merely illustrative of the principles of the disclosure, which may be applied in various ways to provide many different alternative embodiments and may be applicable outside the fields of surgery or medical devices. While the present disclosure is made in the context of facet joints in the lumbar spinal region for the purposes of illustrating the concepts of the design, it is contemplated that the present design and/or variations thereof may be suited to other uses, such as cervical facet joints, thoracic facet joints, other joints in the human body, or to stabilize bone fractures, etc. Moreover, the implants, instrumentation and methods set forth herein may be used in open, percutaneous, and/or minimally invasive procedures and may be placed via intra-facet, trans-facet, trans-laminar, or trans-pedicle means.
All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Standard medical planes of reference and descriptive terminology are employed in this specification. A sagittal plane divides a body into right and left portions. A mid-sagittal plane divides the body into equal right and left halves. A coronal plane divides a body into anterior and posterior portions. A transverse plane divides a body into superior and inferior portions. Anterior means toward the front of the body. Posterior means toward the back of the body. Superior means toward the head. Inferior means toward the feet. Medial means toward the midline of the body. Lateral means away from the midline of the body. Axial means toward a central axis of the body. Abaxial means away from a central axis of the body. Ipsilateral means on the same side of the body. Contralateral means on the opposite side of the body. These descriptive terms may be applied to an animate or inanimate body.